There are in fact many variations of this idea, and it's actually more popular than you might think. It's an intuition that I share.
If you want two relatively well-formulated elucidations of the idea, see Max Tegmark's Mathematical Universe and Stephen Wolfram's Ruliad. These are both (arguably isomorphic) different interpretations of the idea. Max Tegmark's idea is that every mathematical structure exists, and that our universe is in fact a mathematical structure. Stephen Wolfram's idea is quite similar, except instead of centering on Mathematical Structures he focuses on Computation - all computations "exist", all algorithms "exist", everything computable "exists", and this universe is one of the infinite structures in that realm.